Combination fused switch



I938. E. G. JOHANSSON 2,123,647

I COMBINATION FUSED SWITCH I Filed Dec. 6, 1955 2 Sheets-Sheet 1 QZwzzir 2/ 5 W12 file/220% a d ,1 E. G. JOHANSSON 2,128,647

COMBINATION FUSED SWITCH \H n I I W "/4 f, g i Wag/whamm- Cal PatentedAug. 30, 1938 UNITED STATES 2,128,641 7 COMBINATION FUSED swrrcn ErnestG. J ohansson,

Watertown, Mass, as-

signor to The Palmer Electric & Manufacturing 00., Waltham, Mesa, acorporation of Massachusetts Application December 6, 1935, Serial No.53,168

Claims.

This invention relates to a fused electric switch in a casing orcabinet, having a door or doors which, when closed, tightly close thecasing without overlapping'the exterior of the casing walls and which,when wide open, do not overlap any portion of the area bounded by theside walls of the casing.

Devices of this character are in some instances installed in multipleunits with the side or end walls closely adjacent or actually abuttingeach other, and in other instances are individually embedded in aplastered wall and supplied with an apron or trim to conceal the jointsbetween the cabinet and the wall. To efiect economies in space in theinstallation of the devices in multiple or to permit the installation ofthe apron or trim when the cabinet has been embedded in a plaster wall,it is desirable that the exterior of the cabinet be flush with the wallsurface. It is also desirable that the door or doors and apron of thecabinet be so arranged that the doors may be swung open withoutdisturbing the apron, to afford unimpeded access to the interior of thecabinet for inspection, removal or replacement of any of the elementscontained therein.

it is an object of the invention to provide a switch, compact instructure and simple in operation, which is adapted for use in circuitscarrying relatively heavy currents, as for electric power units. It is afurther object of the invention to provide a switch box or cabinetcontaining one or more fused switches, the cabinet structure be ing suchthat the fuses are necessarily disconnected from all sources ofelectrical energy when exposed for handling, and the live parts of theswitch or switches are emciently shielded from manual contact by meansof a barrier member whichis removable to permit access to the live partsiorinstallation or inspection purposes. The box or cabinet structure isalso such that the fuses are accessible for inspection or replacementwhen the box is open, and the door or doors, when shut, close thecabinet tightly so as to prevent egress of flame when an electric arcoccurs in the cabinet, as, for example, when a fuse blows therein.

According to the invention, a switch box or cabinet is provided whichmay have one or more switch units therein, such as a main switch, apower switch, and fused connections for lighting circuits. in thecabinet the live parts and the wiring associated therewith are shieldedby a dead-front partition from being accidentally touched. Thispartition is preferably removable to permit inspection of the switchmembers and wiring contained in the rear compartments of the box. Thecover of the box is preferably in the form of one or more separatesections or doors which can be independently opened, each door or coversection corresponding to one of the switches in the box or to the fusedconnections for the lighting circuits. One or more of the doors maycarry switch elements adapted to cooperate with corresponding elementsmounted in the box, and also fuses associated with such switch elements.Each door is preferably provided with flanges which effect a tightclosure of the corresponding portion of the cabinet before the closingmovementof the door connects the fuse carried thereby into the circuit.

For a more complete understanding of the invention, reference may be hadto the description thereof which follows and to the drawings of which--Figure 1 is a front elevation of an embodiment of the invention showingpart of the box cover closed and part open.

Figure 2 is a perspective view of a dead-front partition member adaptedto be secured in the box.

Figure 3' is a section on the line 3-3 of Figure 2.

Figure 4 is a perspective rear view of the box showing a flush apronattached thereto.

Figure 5 is a section on the line Ir-5 of Figure 1.

Figure 6 is a section on the line 6-45 of Figure 5.

Figure 7 is a wiring diagram of the electrical apparatus contained inthe box.

Figure 8 is a perspective view of a box having a different arrangementof the units.

In the embodiment of the invention illustrated in Figures 1 to '7, theinvention comprises a sheet metal switch-box or cabinet iii adapted tobesecured in an uprightpcsition against a wall or partition of abuilding, or to be sunk in a wall flush with the surface thereof.Secured to the rear wall of the box iii is a block E2 of insulatingmaterial on which are mounted switch teranimals it of any desired orsuitable form, these switch terminals being preferably of a form adaptedto cooperate with switch blades so as to close the circuit. The blocksit are secured to the rear wall of the box ill, preferably by means ofscrews passing through holes in the rear wall of the box. This permitsadjustments of the contacts when the cover is closed. The block 82 ofinsulation is preferably provided with a ridge portion l8 which projectsfurther forward than the terminal elements M so that it constitutes aspacing element of insulating material separating terminal elements ofopposite polarity.

As indicated in Figure 7, the box l0 may be provided with two switchblocks 12, one of which is mounted in the upper portion of the box, theother being mounted in the lower portion of the box. Between these twoswitch blocks may be mounted a base member 20 of insulation on which area number of plug-fuse sockets 22, four such sockets being illustrated.As shown, .the line wires 24 may enter the box and be connected tocertain of the switch terminals H, and conductors 26 may lead from theother terminals 14 of the upper switch to a pair of terminals of thelower switch. Load wires 28 may be connected to the other terminals ofthe lower switch, wires 28 preferably leading to a range or some otherelectric unit requiring a relatively heavy current. Connections to thefuse-receiving sockets 22 may be tapped off from the conductors 26 in amanner well known in the art, the fuses in the sockets 22 being employedto control lighting circuits connected therewith.

In order to shield the live members in the box from accidental contactby the fingers of a person operating any of the switches, a dead-frontpartition member 30 may be provided, such memher being illustrated inFigure 2. As therein shown, this member may consist of a sheet of metalhaving a bottom portion 32 and side walls 34 bent up therefrom.Extending from one side wall to the other are a pair of partitionmembers 36 which divide the space between the side walls 34 into threecompartments corresponding respectively with the upper switch, thecentral fuse block for the lighting circuits, and the lower switch. Asthe sheet metal of which the partition members 35 are made is preferablysimilar to or lighter than the stock usedfor the walls of the cabinet,the effective width of the forward edges of the partition members ispreferably increased as by bending back a portion 31, for purposeshereinafter set forth. The bottom portion 32 of the dead-front member isprovided with large apertures in the upper and lower compartments,sheets of insulating material in being secured over such apertures toclose the same. As illustrated in Figure 3, a pair of insulation sheetsmay be provided for each aperture, these sheets being held together byrivets 42 or any other suitable means. The insulating sheets 40 areprovidedwith narrow slots ll located over respective terminals I4 andadapted to receive switch blades as hereinafter described. The middleportion of the bottom 32 of the dead-front member is preferably providedwith an aperture 48, which, as shown, may be in clover-leaf form toexpose the four sockets 22 so that fuse plugs may be inserted therein orremoved therefrom without disturbing the dead-front member. As indicatedin Figure 5, the rear wall 32 of the dead-front member may abut theportions l6 of the switch block l2. If desired, a transverse partition50 may be mounted in the box to extend from the rear wall thereof to thedead-front member, thus dividing the space behind the dead-front memberinto two separate compartments.

The box I0 is preferably provided with custornary knock-outs 52 formedin the side and rear walls thereof to facilitate the entry of wiresthrough the rear of the box or through any of its sides. All of theseknock-outs are rearward of the dead-front member 30, so that this membershields not only all of the terminal elements mounted in the box, butalso all of the wiring within the box. The dead-front member may beremovably held in place by any convenient means. As shown, the sidewalls 34 each have a central aperture 54 to receive a machine screw 56which projects through the opening and is screw-threaded into the sidewall of the box in. The rear wall or bottom portion 32 of the deadrrontmember is approximately of the same length and width as the interior ofthe box so that its side and end edges abut the side and end Walls ofthe box, completely shielding the apparatus in the box behind thedead-front member. The side walls 34 of the dead-front member preferablyfit snugly against the side walls of the box so that their engagementwith the walls of the box, together with the abutting engagement of therear wall 32 of the dead-front member with the insulating blocks i2,provides a firm seating for the dead-front member in the box. Byremoving the screws 56, however, the dead-front member can readily betaken out, thus exposing all of the electrical apparatus in the box.

The cover of the box is preferably made in a plurality of separatesections, each section corresponding to a portion of. the apparatusbehind the dead-front member. As shown in Figure 1, the cover of the boxconsists of three sections or doors B0, B2 and 64, these doorsregistering respectively with three compartments formed by the partitionelements 36. On the inner faces of the doors 60 and 54 are mountedinsulating blocks I0 which carry switch blades 12, and, if

desired, fuse holders 74. These blocks are secured to the doors,preferably by means of screws 15 passing through holes in the doors. Asshown, the fuse holders are adapted to receive cartridge fuses 16 in amanner well known in the art. The switch blades 12 are adapted toproject through corresponding slots 44 when the doors are swung shut,the ends of the blades coming into contact with the respective terminalsl4 behind the deadfront member. In order to protect the user frompossible contact with a charged part, the doors and 84, which carryswitch blades T2, are provided with flanges 80 adapted to telescopeinside the walls of the respective compartments closed by these doors.The flanges 80 are preferably turned downwardly from a plate 81. Theplate 8| is preferably positioned on the cover by screws 15 passingthrough holes in the cover and plate. The width of the flanges 80 issufllcient to cut oil access to the interior of the forward compartmentsof the box before theswitch blades 12 come into contact with theirrespective terminals ll, so that, when the switch blades T2 areelectrically charged, they are not accessible and cannot be touched bythe fingers of the user. The door 82 is also provided with a flange 8|which need not be made as wide as the flange 80. The

flanges 80 and 8! are offset from the four side edgesof their respectivedoors so as to give the doors an emoiently rabbeted structurecooperating with the walls and partitions of the box, when the doors areclosed, to form a closure such that the crack or, clearance between themarginal portion of each door and the adjacent box walls will have anangle therein. That is, when a door is closed, at no point can astraight object like a pin be thrust through the crack between the doorand box walls. To this end, in-

order to receive the marginal portions of the doors, the partitionmembers 35 are widened at their forward edges, as hereinbeforedescribed,

this being done by any suitable means as, for example, a bent-backportion 31.

It is also desirable that the flanges 80 and BI engage the adjacent boxwalls and partition members frictionally so as to hold the doors againstbeing accidentally or too easily opened. While it may not be practicalin actual manufacture to fit the flanges 80 and BI into the compartmentsso accurately that they will have continuous engagement with the wallsand partitions when shut, the flanges can be fitted for frictionalcontact with the walls and partitions at several points. Such engagementis facilitated by the bent back portions 31 of the partition members 36which permit slight resilient yielding when engaged by the flanges ofthe doors.

For compactness of structure, the doors 60, 62 and 641 may convenientlybe hinged to the box ill by a piano-type of hinge consisting ofalternate elements integral with the side wallof the box, the otherelements being integral with the doors of the box. Each of theseelements preferably consists of a tongue projecting from an edge of theside wall of the box or one of the doors of the box and curled asindicated in Figure 6 to receive a hinge pin. The tongues or elementsare spaced, the spaces having the same width as the tongues so that theelements of the side wall of the box fit into the spaces between theelements on the box doors, and vice versa. A single hinge pin 82 mayproject through all of these elements. This results in a hinge structurewhich projects but slightly beyond the planes of the outer faces of theadjacent side wall and doors of the box. With hinges as shoum, cabinetsmay be mounted side by side practically in contact, but the doors may beswung wide open without interference with adjacent cabinets. If acabinet is mounted in a wall so as to be sub stantially flush with theface thereof, the hinge structure projects out slightly from the planeof the wall and doors. but such projection is hardly observable. Byproviding a piano-type hinge having tongues integral with the door inwhich holes for the screws 15 are located and having alternate tonguesintegral with the box ill in which the screws i are located, exactalignment of the switch members secured by those screws is madepossible. Furthermore, the flanges 8'1 are accurately aligned by reasonof the fact that they are positioned on the cover by screws I5 passingthrough holes in the plate Bl. For flush mounting in a wall, a suitableapron 84 may be provided. this apron being secured to the box flush withthe doors-thereof by'any suitable means such as a series of bracketelements 86, which, as shown, may be attached by bolts to the bottom ofthe box and to the apron.

The apron may be in the form of a hollow rectangle which fits snuglyaround the front contour of the box, including the hinge. The bracketmembers 86 are preferably of such a length that the apron is held in thesame plane as the doors when the latter are shut. As thus arranged. thedoors may be swung wide open to permit the removal of any of thecontents of the box, including the dead-front partition member 30,without disturbing the apron or the box itself.

The several doors 6!], 62 and 64 may each be provided with a suitablebail or handle 88 whereby they may be readily swung open. If desired,suitable lugs 90 may be provided with one or more of the doors so thatthey may be sealed shut as indicated at 92 in Figures 1 and.6. Thesealing lugs 90 are preferably pivotally mounted on the front partitionmember box wall so that they can be swung clear of the plane of thedoors so as not to" interfere with the apron when an apron is mounted onthe box as described.

The invention is illustrated as embodied in a cabinet having threeunits; It may also be embodied in cabinets having one, two or moreunits. Instead of having three units in the box arranged in verticalarray as illustrated in Figure 1, various other arrangements arepossibleas, for example, that illustrated in Figure 8. As therein shown,the portions of the box containing the main and heater switches arearranged side by side, the portion of the box containing the fusesockets for the lighting circuits being below the other sections. It isevident that other convenient arrangements are possible.

The invention herein shown and described is capable of variousmodifications and changes without departing from the spirit or scopethereof as defined in the following claims.

I claim:

1. Apparatus of the class described, comprising a fused switch boxconsisting of a back wall,

side walls and end walls, said side and end walls having knockoutstherein, insulated switch terminals mounted in said box, a dead-frontpartition member removably mounted in said box, said partition memberbeing spaced from the back wall of the box and abutting all the side andend Walls thereof to mask all said switch terminals and associatedwiring, a cover hinged to said box, switch elements carried by saidcover and movable therewith into engagement with said switch terminalswhen the cover is closed, and fuse-holding elements mounted on saidcover and electrically connectedwith respective switch elements, saidpartition member having a portion of insulating material with openingstherethrough for said switch elements.

2. Apparatus of the class described, comprising a switch box consistingof a back wall, side walls and end walls, said side and end walls havingknockouts therein, a. dead-front partition member removably secured insaid box and abutting all the side and end walls thereof, switchterminals mounted in said box between the back wall thereof and saiddead-front member, a cover member hinged to said box, switch structureincluding contact blades mounted on said cover and movable therewith tocause said blades to engage said terminals, said dead-front memberhaving narrow slots therethrough to receive said blades when the coveris swung, shut, and a flange projecting from the inner face ofsaid covermember and of sufllcient width to telescope within the box walls so asto cut off access to said switch structure before said blades move intocontact with said terminals.

3. Apparatus of the class described. comprising a metal switch box, aplurality of insulation b ocks secured to the rear wall of said box.switch terminals mounted on said'blocks, each said block having aportion extending further forward than any of the terminals mountedthereon, a deadremovably secured against said blocks and extending tothe side and end walls of the box, said dead-front member having aportion of insulating material slotted to receive contact blades forengagement with said terminals, and a plurality of cover members hingedto said box, each said cover member having thereon switch structureincluding contact blades adapted to engage the terminals carried by oneof said insulation blocks.

4. Apparatus oi the class described, comprising a switch box, aplurality of switch blocks mounted on the rear wall or said box, switchterminals mounted on said blocks, a dead-front member removably securedin said box in front of said blocks, said member consisting of a metalsheet having approximately the same length and width as the interior ofthe box, side walls extending forward from said sheet and lying againstthe side walls 01' the box and transverse partition elements extendingfrom one side wall 01' said member to the other to form therewith. aseries of compartments, said metal sheet having substantial aperturestherethrough registering with said switch blocks, plates of insulatingmaterial secured over said apertures and provided with narrow slots, acover on said box, and switch elements carried by said cover and adaptedto project through said slots when said cover is,

member dividing the space in,the box formed.

in the dead-front member into three compartments correspondingrespectively to the live terminals, the load terminals and the lightingcircuit connections, three cover elements hinged to the box andindependently swingable to open and closed positions, each said coverelement registering withone of said compartments, and fuseholding switchstructure mounted on two ofsaid cover elements and including bladesmovable through said slots into contact with respective line and loadterminals.

6. Apparatus of the class described, comprising a switch box havingknock-outs in the walls thereof, a set of line switch terminals and aset of load switch terminals mounted within said box, a dead-frontpartition member rerriovably secured, in, said box and forming thereinRent and rear compartments, said partition member abutting all the side-and end walls of the box forward-o! the knock-outs whereby all wiringentering the box is behind said partition member, a pair or separatelyoperable cover members hinged to said box, each said cover membercarrying switch structure including fuse-holding elements and contactblades adapted to move into contact with a corresponding set or saidswitch terminals, said partition member having narrow slots therethroushto receive said blades, and forwardly-proiecting partition means on saidpartition member subdividing said forward compartment so that, wheneither of said cover thereby is entirely enclosed.

V. Apparatus of the class described, comprising-a switch box havingknock-outs in the sides thereoi, insulation members mounted in the box,switch terminals mounted on said members, a dead-front partition memberremovabiy secured in said box, said partition member being spaced fromthe back wall of the box and abutting all the side and end walls thereofto mask all said switch terminals and associated wiring, a cover hingedto said box, switch structure including fuse-holding elements andcontact blades mounted on said cover, said blades being arranged to moveinto contact with said terminals when the cover is closed, saidpartition member having narrow slots for the projection of said bladestherethrough, and a flange on the periphery of said cover adapted totelescope within the box as the cover closes so as to cut off access tothe said blades before they move into contact with said terminals.

8. Apparatus oi the class described, comprising a sheet metal switchbox, a cover member hinged to said box, switch elements mounted withinsaid box, cooperating switch elements mounted on said cover member, asheet metal flange on said cover member spaced inwardly from the edgethereof and arranged to telescope within the walls of said box withyielding frictional engagement when the cover is closed and ofsufficient width to cut oil access to said switch elements before theswitch is closed.

9. Apparatus of the class described, comprising a switch box, a covermember hinged to said box, switch elements mounted in said box,cooperating switch elements mounted on said cover, a dead-frontpartitionmember shielding the ele ments mounted in said box and provided withapertures to receive the elements mounted on said cover when the covermember is closed, and a flange on the'cover member telescoping withinthe walls of the box when the cover is closed and oi! suflicient widthto cut of! access to said switch elements before the switch is closed.

10. A sheet metal box having a cover therefor hinged to thecorresponding side wall of the box,

a set of binge members formed directly from the said side wall, a secondset or hinge members formed directly from said cover, said hinge membersbeing disposed in alternate and abutting relationship on a hinge pin, aplate secured to the cover, said plate having flanges thereon extendinginwardly so as to telescope within the box when the cover is closed, afixed switch member mounted on the rear wall of the box, a second switchmember mounted on the cover and movable therewith into engagement withthe first switch member, said flanges being of sufficient width to cutoil access to said switch elements before the switch is closed, mountingmeans for said switch members and said plate including holes ln'the rearwall and the cover, said holes being spaced with relation to said hingemembers to insure substantially accurate engagement between the switchmembers and between the flanges and the inner walls of the box when thecover is in closed position.

ERNEST G. JOHANSSON.

